Latitudinal distribution of mycorrhizal types in native and alien trees in montane ecosystems from southern south America

Abstract

Biological invasions constitute a global environmental threat that rapidly alters natural communities and ecosystem functioning. A way to understand the success of alien trees in novel ecosystems is by comparing their ecological strategies with those of natives. Plants often associate with mycorrhizal fungi in their roots to enhance nutrient acquisition. According to fungal identity, morphological structures and functioning, different types of mycorrhizas can be distinguished. Despite the phylogenetic imprints that often characterize mycorrhizal distribution among plants, it is well known that mycorrhizal types vary across environmental gradients, vegetation types and plant life forms. Then, at the global scale, the different types of mycorrhizas are not randomly distributed across biomes but rather related to environmental variables. In this chapter we examine the patterns of mycorrhizal distribution in native and alien tree species occurring in contrasting montane ecosystems across a broad latitudinal gradient in South America. We analyze whether patterns of mycorrhizal distribution in alien trees tend to converge or diverge with those in observed in natives. From the analyses we conclude that patterns of mycorrhizal distribution in alien and native trees occurring in montane ecosystems from subtropical to temperate regions, roughly follow those predicted by models of mycorrhizal distribution at global scales. This is seemingly in line with the idea of broad scale environmental filters driving predominance of convergences in the functional strategies of coexisting tree species along these mountain biomes. Nonetheless, ECM in aliens is in higher proportion compared to natives, particularly in temperate forests. Results of this chapter suggest that mycorrhizal associations have an unambiguous role in tree invasions in montane forests across different climates. However, they also reveal that the relative importance of each mycorrhizal type in each ecosystem remains to be determined.